Top burner control for gas ranges



1962 w. A. RAY 3,058,665

TOP BURNER CONTROL FOR GAS RANGES Filed Dec. 24, 1959 IN VEN TOR. WALL/4M 4 84;

W 9% 47' 7' GPA/E 1 5- 3,058,665 TOP BURNER CONTROL FOR GAS RANGES William A. Ray, North Hollywood, Calif., assignor to General Controls (30., Glendale, Calif, a corporation of California Filed Dec. 24, 1959, Ser. No. 861,851 4 Claims. 13i. 23620) The present invention relates generally to a thermostatically controlled valve and particularly one which controls the flow of gas to the top burner of a gas stove hav ing a heat-sensing element in contact with a cooking utensil on such burner, although in its broader aspects the present invention is applicable also to other gas-controlled heating systems such as, for example, space heaters and the like.

One of the main problems encountered in a top burner thermostatic control arises from the fact that a relatively small gas flow must be controlled to maintain a constant temperature of, for example, 200 F. in a small cooking vessel on the burner, such gas flow being usually less than a flow of 800 B.t.u. below which the burner flame tends to flutter and become extinguished.

Previous attempts have been made to solve this problem by modulating the burner from an On condition to an 013? condition, ie in the range between 800 B.t.u. and B.t.u., while maintaining a small stand-by pilot flame adjacent to the burner ports. As the gas flow is modulated up and down in the range between 800 and 0 B.t.u., the burner operation is erratic and raw gas is usually released, resulting in an objectionable gas odor due, for example, to the aldehydes therein which have a distinct and powerful odor. This condition may also lead to flash back with the gas igniting at the burner orifice and further to additional combustion problems resulting from the loss of gas velocity at the orifice at very low inputs due to throttling of the gas upstream from the orifice.

In accordance with an important feature of the present invention, a single valve is used to accomplish both a modulating and snap-controlling action. In accordance with prior art practice two valves are provided, i.e., a modulating valve for operating between minimum and maximum flame, and a second snap valve for snapping off the minimum flame.

Such single valve, in accordance with features of the present invention, is temporarily restrained from further closing movement when the minimum flame position has been reached; and, further increase in temperature caused by gas escaping in such minimum flame position causes a build-up of forces which eventually overpower the restraining member. As soon as the restraining member starts to yield, there is sufficient stored energy in the various resilient portions of the mechanism to cause the valve to snap to the closed position. Subsequently, as the temperature drops, the closing forces relax to the point where the magnet is capable of abruptly opening the valve to the minimum flame position.

It is therefore an object of the present invention to provide an improved control system of this character which overcomes the above-indicated difficulties encountered in the prior art arrangements.

A specific object of the present invention is to provide an improved system of this character in which a thermostatically controlled valve is incorporated featured by the fact that substantially full velocity of the orifice stream is maintained at all inputs.

Another object of the present invention is to provide a" control system of the type indicated in the preceding paragraph in which the valve is a needle valve or a Valve similar to the needle valve.

3,058,665 Patented Oct. 16, 19 62 Another object of the present invention is to provide a valve arrangement of this character in which modulation preferably accomplished with a snap action is obtained using a single needle valve or a single valve similar to a needle valve.

Another object of the present invention is to provide an improved thermostatically operated valve which is particularly useful in a system of this character.

Another object of the present invention is to provide a gas control of this character in which the flow of gas is continuously modulated from a predetermined maximum rate to a predetermnied minimum rate and in which the flow of gas is abruptly shut off when the flow rate tends to fall below such predetermined minimum rate.

Another object of the present invention is to provide a control of the character set forth in the preceding paragraph in which adjustable means are provided for adjusting such predetermined maximum rate.

Another object of the present invention is to provide a gas control of the character set forth in the two preceding paragraphs in which the flow of gas occurs at a substantially constant value during its modulation in the range between such maximum and minimum values.

Another object of the present invention is to provide an improved gas control of this character for a burner having associated therewith a venturi section for inspirating air, the control being characterized by a single movable valve element for continuously modulating the flow of gas into such venturi section at a substantially constant speed within the range of continuous modulation.

Another object of the present invention is to provide a control as set forth in the preceding paragraph in which such single movable valve element is operated to a closed position with a snap action when the gas flow rate falls below a predetermined minimum rate.

Another object of the present invention is to provide a gas control of this character for maintaining a substantially constant temperature in the vicinity of a gas burner, there being provided for this purpose thermostatic means responsive to temperature in the burner for continuously modulating the rate of gas flow between a maximum and a minimum value with such thermostatic means functioning also to cause the valve to snap to closed position when the gas flow rate tends to fall below such minimum value.

Another object of the present invention is to provide a gas control of this character which incorporates adjustable means for establishing such substantially constant temperature.

Another object of the present invention is to provide a control of this character in which the flow of gas is controlled at two different rates depending on temperature conditions together with means for preventing the flow of gas when the gas flow rate tends to fall below a minimum value.

Another object of the present invention is to provide an arrangement of this character in which the valve modulates relatively slowly in response to temperature changes between the maximum and minimum flame positions and then modulates abruptly from the minimum position to Off in response to a further increase in temperature, there being a relatively slow modulation of gas flow in accordance with changes in temperature within a continuous controlling range corresponding generally to a range between a maximum and a minimum temand inexpensive means functioning essentially with a snap action without the cost and/ or complexity of a snap mechanism.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 illustrates a top burner control system incorporating features of the present invention.

FIGURE 2 illustrates more details of the thermostatically operated valve shown in FIGURE 1.

FIGURE 3 illustrates another form of the present invention.

In FIGURE 1 there is illustrated a top burner for a conventional household cooking stove which incorporates, in conventional manner, a centrally positioned spring-biased temperature-sensing element 11 for contacting and sensing the temperature of the bottom of a cooking vessel (not shown) resting on such burner.

Also associated with such burner 10 is a small pilot burner (not shown) which is continuously ignited to assure burning of all of the gas controlled by the valve structure 12 constructed and functioning novelly in accordance with important features of the present invention.

This valve structure indicated generally at 12 in FIG- URE 1 involves a movable valve element 13 cooperating with its fixed valve seat or orifice 14 for controlling the flow of gas into the air-gas mixing chamber 15 leading to the venturi section 16 and the burning ports of burner 10. The flow of air may be controlled by an adjustable shutter 18 surrounding the chamber 15.

As the gas flow is reduced by forward movement of the needle valve element 13 in its orifice 14, substantially full velocity of the gas stream through such orifice is maintained, assuring proper air inspiration and optimum flame characteristics at reduced B.t.u. inputs. This needle valve element 13 is controlled thermostatically in response to the temperature sensed by the sensing element 11.

The orifice 14 is mounted in the valve body 20 in such a way that it injects a gas stream directly into the burner venturi tube 16, the gas being introduced into the chamber 20 through its threaded opening 21 which is in communication with the gas manifold 22 (FIGURE 1).

The stem of needle valve element 13 is guided in guide fins 2.4 which, of course, allow gas flow to the orifice 14 and such element 13 is actuated by lever 25. When the valve element 13 is mounted in a vertical position as shown in FIG. 2 gravity forces alone acting thereon may move the element downwardly and when the element 13 is mounted horizontally as shown in FIG. 1 a compression spring may be interposed between flanged portion 13E and the inside of casing 12 to achieve the same result as gravity forces. This latter spring is designated as spring 17 in FIG. 2.

Lever 25 has one of its ends bearing on an adjustable stem 26 threaded in housing 20 and the prestressed coil compression spring 29 acting between the housing 20 and an intermediate portion of lever 25 presses the same into engagement with both the stem 26 and the movable lever seat 27 which is positioned between lever 25. and the movable end of expansible bellows 28.

Bellows 28 is expanded in increased amounts with increasing temperatures sensed by element 11 and details of the same may follow conventional practices in which a capillary tube 30 filled with a suitable fluid extends between the sensing element 11 and bellows 28.

The other end of lever 25 supports the movable valve element 13 which is of hollow construction to allow gas to flow not only between its tapered end and the complementary tapered wall of orifice 14 but also through the interior of the same through a path which includes circumferentially arranged apertured portions 13A in the enlarged cylindrical portion 13B. This latter path may be closed, as described later, upon movement of the valve disc 13C against its annular raised valve seat 13D which extends from the flanged portion 13E. This disc is normally biased away from its seat 13D by the coil compression spring 13F acting to press the disc 13C against the disc-retaining lip 13G.

It will thus be seen that upon increase in temperature the lever 25 is pivoted counterclockwise (FIGURE 2) about the adjustable abutment 26. The needle valve element 13 follows such movement of lever 25 with the valve 13C, 13D remaining open until the tapered end of valve 13 contacts the complementary wall of orifice 14, after which the valve 13C, 13D is closed to completely shut 011 the flow of gas.

In operation of the arrangement shown in FIGURE 2, it is initially assumed that the sensing element 11 is in a cold but preheated condition, i.e. it calls for heat and the parts are in the positions illustrated. It is noted that in the extreme cold condition of element 11 the bellows 28 is deflated and the movement of lever 25 and needle valve element 13 is arrested by the threaded stem 41 of adjustable knob 40 which is preadjusted to establish the maximum burner flame, i.e. the maximum opening between valve element 13 and its orifice 14. As the temperature of the sensing element 11 rises, the bellows 28 expands to, for example, the position shown in FIGURE 2, still allowing the flow of gas through orifice 14 and through its tubular portion, i.e. through apertures 13A, at substantially the same velocity but in smaller quantity, i.e. smaller B.t.u. rate. As the temperature of element 11 increases further, the valve 13, 14 closes but the valve 13C, 13D remains open. Upon further increase in temperature, the biasing force of spring 13B is overcome and the valve 13C, 13D is closed. Because the diameters of the movable valve element 13D and its seat 130 are much greater than the diameter of the elongated tubular portion of valve 13 and its orifice 14, the valve 13C, 13D closes abruptly, in a form of snap action.

Thus, the valve 13, 14 closes at a predetermined gas flow rate at, for example, 800 B.t.u. which flows then through the central hollow portion of valve 13, i.e. through apertures 13A which are so sized as to allow such minimum flow rate.

Should the sensing element 11 still continue to call for a smaller rate of gas flow than that supplied through apertures 13A, the valve 13C, 13D is closed with a snap action to allow the heated vessel and sensing element to cool to a temperature at which the valve 13C, 13D is reopened with a snap action. In other words, flow of gas at rates less than 800 B.t.u. is prevented but when the required input exceeds 800 B.t.u., the valve element 13, 14 is also allowed to open and the element 13 modulates between a full open position, established by stem 41, and. the 800 B.t.u. condition established by the apertures 13A.

It will be noted further that the temperature at which such snap action of the valve 13C, 13D occurs may be adjusted by adjustment knob 26A, movement of the stem 26 outwardly in the housing 26 serving to establish a lower operating temperature which is maintained substantially constant in the manner described above with the valve 13C, 13D being periodically snapped to closed and open position. Conversely, movement of the stem inwardly results in maintenance of a higher operating temperature which may be sufiiciently high to permit maintenance of a substantially constant temperature without any snap action, i.e. by modulation or movement of the valve 13 with respect to its seat 14 between positions corresponding to the end of stem 41 and the position at which valve 13, 14 closes.

While the drawings show my preferred form of a pointed needle valve element 13 cooperating with a mating tapered orifice 14, the form of the valve may be different, i.e. it may comprise a small diameter rod projecting in varying degrees in a circular seat with, for example, a flange on the rod cooperating with an adjacent circular seat for full closure of the valve.

In the modification shown in FIGURE 3 there is again provided the adjustable abutment 26, the bellows 28 with the coil compression spring 29 acting between an intermediate portion of lever 125, corresponding to lever 25, and the movement of lever 125 may again be limited by the adjustable stop member 41 as described above. In this case, however, the needle valve element 113 is solid and again has a tapered end cooperating with a complementary tapered orifice 14.

This lever 125 has a second lever 126 fulcrumed thereon about the fulcrum 127 and this lever 126 is normally pressed against the stop 128 on lever 125 by coil compression spring 130 acting between lever 125 and one end of lever 126. The other end of lever 126 engages the topside of the valve flange 113A, being pressed into engagement by the coil compression spring 132 acting between lever 125 and the bottomside of valve member 113.

In operation of the arrangement shown in FIGURE 3, maximum gas flow through valve 113, 14 occurs in the extreme cold position, i.e. when lever 125 engages the adjustable abutment 41. Upon rise in temperature of the sensing element 11, the bellows 28 expands to the position shown in FIGURE 3 to move levers 125 and 126 as a unit with substantially no relative movement between levers 125 and 126 since lever 126 remains biased against stop 128 by spring 130. However, the valve element 113 moves relative to the orifice 14 to modulate the gas flow rate which fiows, during such modulation, at a substantially constant velocity.

Upon further increase in temperature, the righthand end of lever 126 engages the adjustable stop 134 so that the left-hand end of lever 126 may then move at a faster rate than lever 125 because of the resulting motion magnification provided by the lever system. This means that on continued rise in temperature after lever 126 engages stop 134, the lever 126 moves relative to the lever 125 to allow the valve 113 to move quickly to closed position under the influence of spring 132. The stop 134 is thus adjustable to provide a minimum flow rate below which the valve 113, 14 is closed at a relatively rapid rate simulating a snap action. It will be seen that the valve 113, 14- opens with a like snap action when the temperature is subsequently lowered.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall Within the true spirit and scope of this invention.

:1 claim:

1. In a gas control of the character described, means forming an orifice, a hollow movable valve element having an exterior portion cooperating with said orifice to continuously control the :flow of gas through said orifice over a range extending from a maximum rate to a rate which is substantially greater than a zero rate, said valve element incorporating normally open valve means allowing the flow of gas through said valve means, through said hollow element and through said orifice, valve element moving means, thermostatic means responsive to a temperature condition for continuously operating said moving means to initially move said valve element into engagement with said orifice and then subsequently to close said valve means.

2. A control as set forth in claim 1 in which said valve element comprises a needle valve having a tapered end cooperating with a complementary tapered orifice.

3. A gas control as set forth in claim 1 in which adjustable means are incorporated for modifying the effect of said thermostatic means on said valve element moving means to adjust said predetermined temperature value.

4. A gas control as set forth in claim 1 including adjustable means for cooperating with said valve element moving means to adjust said maximum rate.

References Cited in the file of this patent UNITED STATES PATENTS 

